LOCATION PALACIOS TXEstablished Series
TAXONOMIC CLASS: Fine, smectitic, hyperthermic Mollic Natraqualfs
TYPICAL PEDON: Palacios loam--on a nearly level coastal plain in pastureland at 9 feet elevation. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 7 inches; very dark grayish brown (10YR 3/2) loam, dark grayish brown (10YR 4/2) dry; massive; very hard, firm, slightly sticky and slightly plastic; many very fine and common fine roots; common fine pores; neutral; clear wavy boundary. (3 to 8 inches thick)
Btng1--7 to 14 inches; very dark gray (10YR 3/1) clay, dark gray (10YR 4/1) dry; weak coarse columnar structure parting to moderate medium subangular blocky; very hard, very firm, sticky and plastic; common very fine and few fine roots; few fine pores; common thin clay films on faces of peds; moderately sodic; very slightly saline; neutral; clear smooth boundary. (6 to 22 inches thick)
Btng2--14 to 27 inches; dark gray (10YR 4/1) clay, gray (10YR 5/1) dry; few fine faint brownish mottles; weak medium prismatic structure parting to moderate fine and medium subangular blocky; very hard, very firm, sticky and plastic; common very fine roots; few fine pores; many thin clay films on faces of peds; common fine dark concretions; moderately sodic; moderately saline; moderately alkaline; gradual smooth boundary. (12 to 25 inches thick)
Btng3--27 to 40 inches; gray (10YR 5/1) clay, gray (10YR 6/1) dry; few fine dark brown mottles; moderate fine subangular blocky structure; hard, firm, sticky and plastic; few fine roots; few fine pores; common thin clay films; moderately sodic; moderately saline; moderately alkaline; gradual smooth boundary. (12 to 23 inches thick)
BCtng--40 to 70 inches; grayish brown (2.5Y 5/2) silty clay loam, light brownish gray (2.5Y 6/2) dry; common fine faint light olive brown (2.5Y 5/4) mottles; weak fine subangular blocky structure; hard, firm, sticky and plastic; few fine roots; few patchy clay films; many fine dark concretions; moderately sodic; moderately saline; moderately alkaline; gradual smooth boundary. (14 to 32 inches thick)
BCkng--70 to 80 inches; light brownish gray (2.5Y 6/2) silty clay loam, light gray (2.5Y 7/2) dry; many medium distinct olive yellow (2.5Y 6/6) mottles; weak fine subangular blocky structure; hard, firm, sticky and slightly plastic; common fine and medium concretions of calcium carbonate; moderately sodic; moderately saline; calcareous; moderately alkaline.
TYPE LOCATION: Jackson County, Texas; from the intersection of Farm Road 172 and State Highway 35 in Weedhaven, 8.4 miles east on State Highway 35 to Farm Road 3280, 2 miles south on Farm Road 3280 to a shell ranch road, 1.3 miles west on ranch road, and 25 feet south in pastureland.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 60 to more than 80 inches. SAR values range from 2 to 6 in the A or Ap horizon, 13 to 30 in the upper 16 inches of the Bt horizon, and from 13 to 40 to a depth of 80 inches in the Bt and BC horizons. Soil salinity in the A horizon is less than 2 mmhos/cm. In the upper part of the Bt horizon the salinity range is from 2 to 8 mmhos/cm and below it is from 4 to 16 mmhos/cm. Depth to soft masses or concretions of calcium carbonate is more than 28 inches. Dark concretions 1 to 7 mm in diameter range from none to a few throughout.
The A or Ap horizon has hue of 10YR, value of 2 to 3, and chroma of 2 or less. Texture is clay loam, or loam. It is hard or very hard and massive when dry. Some pedons have a few brownish or yellowish mottles. Reaction ranges from slightly acid to slightly alkaline.
The Bt horizons have hue of 10YR, value of 2 to 6, and chroma of 2 or less, and hue of 2.5Y, value of 5 or 6, and chroma of 2. Texture is clay, silty clay, silty clay loam or clay loam. Clay content in the Bt horizon ranges from 35 to 50 percent. Some pedons have brownish or yellowish mottles. Below 28 inches, concretions of calcium carbonate range from none to about 5 percent by volume. Reaction ranges from neutral to moderately alkaline.
The BCtng horizon has hue of 10YR, value of 5 or 6, and chroma of 2 to 6, and hue of 2.5Y, value of 5 or 6, and chroma of 2 to 4. Texture is silty clay, silty clay loam, clay or clay loam. Most pedons have brownish, grayish or yellowish mottles. Concretions of calcium carbonate range from none to about 5 percent by volume. Reaction is mildly alkaline or moderately alkaline.
The BCkng horizon have colors in shades of brown, yellow, pink or red. Mottles of these colors and shades of gray range from none to common. Texture is mainly clay or silty clay. Concretions of calcium carbonate range from none to common throughout. Reaction is slightly alkaline or moderately alkaline.
Some pedons have a 2C horizon below 60 inches that has colors in shades of red, brown or gray. It is very fine sandy loam, silt loam or silty clay loam. Reaction is slightly alkaline or moderately alkaline.
COMPETING SERIES: There are no other series in the same family. Competing series in similar families include Dietrich, Jarron, Livia, Matagorda, Narta, Piasa, and Willamar series. Livia soils have A horizons with value, moist, of 4 or more. Narta soils have less available water in the moisture control section due to greater salinity. Dietrich and Willamar soils are fine-loamy and have mixed mineralogy. Jarron and Matagorda soils have mixed mineralogy. Piasa soils have mean annual temperatures less than 59 degrees F.
GEOGRAPHIC SETTING: Palacios soils are on coastal uplands within 10 miles of the Gulf Coast. Elevations range from 3 to 15 feet, but most areas are below 10 feet. Slope gradients are dominantly less than 1 percent but range to 5 percent near drainageways. Storm surges cover most areas below an elevation of 15 feet once every 10 to 20 years. The soil formed in clayey and loamy sediments of the Pleistocene Age Beaumont Formation. The mean annual precipitation ranges from 38 to 48 inches. The mean annual temperature ranges from 70 to 72 degrees F. The Thornthwaite annual P-E indices range from 48 to 62.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Matagorda series, as well as the Dacosta, Francitas, Laewest, Livia, Telferner and Veston series. Francitas and Livia soils are similar elevations. Dacosta, Laewest, Matagorda and Telferner soils are at slightly higher elevations. Veston soils are at lower elevations. Francitas, Laewest and Veston soils lack argillic horizons. Dacosta and Telferner soils lack natric horizons.
DRAINAGE AND PERMEABILITY: Poorly drained; low runoff on 0 to 1 percent slopes, medium runoff on 1 to 3 percent slopes; very slow permeability. Water perches on top of the natric horizon for periods of 1 to 5 weeks following extended heavy rain.
USE AND VEGETATION: Used for cropland and rangeland. About 60 percent is used for cropland, almost exclusively for rice in a rice-unimproved pasture rotation. A few areas are used for corn and grain sorghum. Native grasses are salt tolerant species such as gulf cordgrass, marshhay cordgrass, seashore saltgrass, low panicums, knotroot bristlegrass and shoregrass. Woody invaders are mostly stunted mesquite, bushy sea-oxeye, and cactus.
DISTRIBUTION AND EXTENT: Texas middle Gulf Coast Prairies. The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Jackson County, Texas; 1986. The name is from a small town in Matagorda County, near the series type location.
REMARKS: Palacios soils were formerly included with the Livia series.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon, intergrading to a mollic epipedon, dark colored, very hard and massive Ap horizon, from 0 to 7 inches.
Natric horizon, the Btn and BCtn horizons at depths of 7 to 70 inches.
Aquic moisture regime as evidenced by low chroma matrix throughout the Btng horizon.